denitrification is a reduction of nitrate by heterotrophic and autotrophic bacteria that may ultimately produce molecular nitrogen (n2) through a series of intermediate nitrogen compounds.vermiculite is a hydrous phyllosilicate mineral (mg, fe+2,fe+3)3[(al,si)4o10](oh)2·4h2o with several layers for bacterial immobilization. the goal of this study was removal of nitrate from water with vermiculi...

nitrate pollutants increase the growth of algal bloom, resulting in fresh water eutrophication. the high nitrogen level in wastewater has become a growing concern, which has risen the necessity to develop efficient nitrogen removal techniques. biological denitrification, which is the reduction of oxidized nitrogen compounds like nitrate or nitrite to gaseous nitrogen compounds, is the most impo...

Eikenella corrodens 33EK(L), a clinical isolate, was assayed for its ability to utilise amino acids as substrates in the reduction of nitrate to nitrite. The metabolism of proline, glutamate, serine and glutamine was found to result in relatively high rates of nitrate reduction. The ability of cells to metabolise these amino acids from a variety of small peptides was also determined. E. corrode...

398 Nitrate and nitrite Nitrate (NO 3 ) is found naturally in the environment and is an important plant nutrient. It is present at varying concentrations in all plants and is a part of the nitrogen cycle. Nitrite (NO 2 ) is not usually present in significant concentrations except in a reducing environment, as nitrate is the more stable oxidation state. It can be formed by the microbial reductio...

The current imbalance in the biogeochemical cycle of nitrogen is as serious as that of carbon. One way to mitigate this problem is through the electrochemical reduction of nitrates under mild conditions, which is an appealing though not fully understood process. Therefore, deeper insight into the electrocatalytic reaction mechanism is needed to optimize this process. Here we thoroughly analyse ...

The synthesis and accumulation of nitrite has been suggested as a causative factor in the inhibition of legume nodules supplied with nitrate. Plants were grown in sand culture with a moderate level of nitrate (2.1 to 6.4 millimolar) supplied continuously from seed germination to 30 to 50 days after planting. In a comparison of nitrate treatments, a highly significant negative correlation betwee...

Nitrogen (N) isotope ratios ((15)N/(14)N) provide integrative constraints on the N inventory of the modern ocean. Anaerobic ammonium oxidation (anammox), which converts ammonium and nitrite to dinitrogen gas (N2) and nitrate, is an important fixed N sink in marine ecosystems. We studied the so far unknown N isotope effects of anammox in batch culture experiments. Anammox preferentially removes ...

The plastoquinone antagonist 2,5-dibromothymoquinone was found to inhibit NO-3 reduction from NADH by the nitrate reductase complex from wheat. It accepts electrons from NADH through the NADH dehydrogenase activity of the nitrate reductase. However, it does not inhibit the reduction of 2,6-dichlorophenol-indophenol by the enzyme. This suggests that the two compounds may be accepting electrons a...

Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their pr...

Stoicheometries and rates of proton translocation associated with respiratory reduction of NO3- have been measured for spheroplasts of Escherichia coli grown anaerobically in the presence of NO3-. Observed stoicheiometries [leads to H+/NO3- ratio; P. Mitchell (1966) Chemiosmotic Coupling in Oxidative and Photosynthetic Phosphorylation, Glynn Research, Bodmin] were approx. 4 for L-malate oxidati...